Field of the Invention
The invention relates to devices and methods for headphone speaker impedance detection.
Description of the Related Art
In the art of electronic circuit design, amplifiers may often be designed to drive loads having indeterminate impedances. For example, an audio power amplifier may be required to drive headphones from a plurality of different manufacturers, and each type of headphone may have different impedance. Furthermore, the impedance of any particular load may change over time, due to factors such as temperature, mechanical degradation, etc.
To optimize power delivery to a load by an amplifier, it would be desirable to determine the load impedance prior to driving the load. In audio applications, for example, this would prevent a headphone from being driven by an unsuitably high output voltage. There is accordingly a need to provide simple and robust techniques for accurately estimating the impedance of a load coupled to an amplifier output.